Explanation: PS4 has a higher clock, but less cores and is using an APU solution (CPU & GPU elements combined onto a single chip). The PS4 has less RAM but is using faster GDDR ram, so the overall performance should be a wash.

Explanation: 720 has a lower clock, but more cores. 720 has more but SLOWER RAM. DDR3 RAM is usually good for things like multitasking etc....It is expected to be based on Windows 8 as well.

Note: GDDR ram is more suitable for Graphics Processing (In PS4), and DDR3 is more suitable for OS Tasks (720). It is expected that the 720 may need some sort of ES/ED Ram to compensate. Basically, don't get caught up in the RAM size but the RAM type.

Note 2: Until OS features etc... are revealed. Nothing concrete can be determined BUT at this point, we can assume both systems would have similar performance.

Update: Added some more info regarding PS4, because apparently my OP makes the PS4 look like shit and has caused confusion hahaha

Just as a side note, the memory setup would be in keeping with the philosophy a Sony VP outlined in a presentation a little while back.

He explained that their opinion was that high bandwidth was a key to rendering performance.

He outlined the PS2 approach - relatively high bandwidth to a relatively small amount of memory.

The PS3 approach - relatively 'medium' bandwidth to a larger amount of memory.

And then said for the future they want the best of both: relatively high bandwidth to a relatively large amount of memory.

I think 4GB-200GB/s would be in keeping with that philosophy.

Microsoft's philosophy, if rumours are true, is obviously different. Relatively small bandwidth to a LARGE amount of memory + high bandwidth to a relatively small amount of memory.

Either could opt for what the other is doing so I think they're both sincerely looking at their own requirements and what developers are asking of them. They've probably come across a lot of various opinions...satisfying all of them would be impossible. Sony was probably told very resoundingly, though, that 2GB was too little, hence the change.

What I'm curious about in Microsoft's case is the talk of Windows 8 and the suggestion that their box might almost present a games machine and a custom W8 'PC' type experience in parallel, each with dedicated resources, perhaps substantial resources for the latter relative to a normal console OS. It would make sense to opt for larger memory over faster memory if that goal is a core one.

What do you mean by the OS? Any game will have a lot of OS calls, whether it be to the networking stack during any online game, the drives, the controller, probably even the GPU. Putting those parts of the OS in a different and much slower part of memory will cause games to grind to a screeching halt every time there's an OS call. Going lower-level on OS functions like threading and memory management makes it even more critical that it's in higher speed RAM.

If you mean background media apps (like Music Unlimited for your custom soundtracks, like on Vita), then the rumored special media processing chip(s) (I'm tempted to just refer to it as the Cell) will likely handle most of the grunt work while the memory-hogging app front-end could be swapped to local storage while it's in the background.

The main thing that's going to be tough is having a browser loaded all the time.

Guerrilla Games (Last major game was KZ3 in early 2011)
Sucker Punch (Last major game was Infamous 2 in mid 2011)
Naughty Dog (Last major game was Uncharted 3 in late 2011)
Evolution Studios (Last major game was MS:Apocalypse in mid 2011)

Then you also have Sony developers who are likely already working on PS4 titles but are not as far along as the above studios:

Polyphony Digital (Last major game was GT5 late 2010)
-This studio is notorious for having ridiculously long development cycles.

Sony Santa Monica (Last major game was GOWIII in early 2010)
-Stig and team #1 has been rumored to be working on a new IP since GOWIII released.

Media Molecule (Last major game was LBP2 in early 2011)
-They are also developing Teraway for PSVita

Of course, this is all based on when these studios last shipped PS3 games along with knowledge regarding how many teams each studio has as well as the timing of previous output from these studios.

EDIT:
Not to mention wildcards like Team ICO moving The Last Guardian to PS4 similar to Ico going PS1->PS2. There are also many "second party" deals Sony likely has in place with studios like Quantic Dream and Insomniac for PS4.

Unless they mean 'true prototype' dev kits, which would make more sense i.e. would make more sense for them to get them first, but if they only got ANY dev kits 12 months after other devs...that would make no sense.

Banned

Q4 2013 is earlier than I expected, and earlier than I'd been hearing around the dev community. Guess Sony doesn't think they can afford to wait past this holiday season with the Xbox successor on the way this year.